Hey Dave, Got my original manual for my '83 D-180, nothing in there about cab spec's, except for # of ohms for cab combinations. Mesa did put in an informational sheet about the D-180, M-180, M-190 & RR enclosures. Mainly marketing with a few numbers. The 2-15 RR had - EVM 15L, weight 128 #'s, argh, should of come with an Arnold Schwarzenegger body building book, dimensions & impedance @ 4 ohms. They noted the 1-15 RR had a 400 watt rated EVM 15L, nothing on the 2-15 RR. The guy at Metro Music in Atlanta back then said it had 2-200 watt speakers. Unsure if that's true, wouldn't know how to tell anyway. No freq response ratings or like numbers in any info I rec'd then. The head and speakers are great sounding, really different from how my recent GAS of 1-15/2-10 Mesa cabs sound. I like the differences, just depends on the mood. Enjoy the tone. John